arm64: zynqmp: Cover ultra96 dts file by MAINTAINERS fragment

Avnet Ultra96 dts file should be also cover by MAINTAINERS fragment.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/board/xilinx/zynqmp/MAINTAINERS b/board/xilinx/zynqmp/MAINTAINERS
index e6fed25..efc1d35 100644
--- a/board/xilinx/zynqmp/MAINTAINERS
+++ b/board/xilinx/zynqmp/MAINTAINERS
@@ -2,6 +2,7 @@
 M:	Michal Simek <michal.simek@xilinx.com>
 S:	Maintained
 F:	arch/arm/dts/zynqmp-*
+F:	arch/arm/dts/avnet-ultra96*
 F:	board/xilinx/zynqmp/
 F:	include/configs/xilinx_zynqmp*
 F:	configs/xilinx_zynqmp*